Building a New Home - Well and Septic Concerns
Within the Municipality of Anchorage
Municipality of Anchorage
We are assuming here that you own a lot and would like to build a home and therefore it is our job to provide a proper wastewater system. Besides the view, access, favorite trees and other personal considerations, the lot owner or builder needs to consider the location of well and septic service on the lot.
The ability of the ground to accept the septic waste depends on the percolation rate of the soil and the ground water table levels.
The typical sequence is to contact an engineer familiar with the local area and provide them with the number of bedrooms of the dwelling and your proposed house location on the lot. This will typically require an onsite lot meeting. If the lot survey corners (rebar or monuments) and boundary are distinguishable then the engineer can get by at this point without a separate survey. If the lot corners or lines are unknown, if there are conflicts or possible conflicts with neighboring improvements, or if there is limited area on the lot, then a survey should be undertaken at this point to determine the exact lot line location and available area for a septic system. This is money well spent and a survey will have to be accomplished at some point anyway for the land use permit plot plan. Many times the location of the septic system over rides the well location and sometimes even the home location in terms of priority. You will want the septic system to be away from existing neighbor wells, low drainage features, surface waters, earth cut banks, driveways and located downhill of the house if possible. Usually there is one clear-cut best location for the septic and it's required reserve or replacement area. We have to design for 2 systems at this time to obtain the initial permit.
The next step is to roughly locate the house, access driveway and the septic tank and leachfield locations. A test hole is then precisely located so that it can prove out the area of the initial leachfield and a future replacement area. This test hole is then excavated as deep as possible or until the groundwater table is reached. A ground water monitor or pvc tube is placed in the hole to determine the stabilized water table level after 7 days. A soil percolation test is accomplished using a hand dug hole in a representative soil layer. The design of the leachfield is dependant on the soil percolation rate and water table level. Here is where it gets complicated as there are 3 types of leachfields and any number of site features can rule one out. A quick calculation can be made at this point and another hole excavated if needed. Sometimes more than one hole is required in order to prove out the replacement area or to explore the lot to determine if there are better soil conditions. A test hole is only good for an approximate 30' radius when completing a design. This is a Municipal requirement. A preliminary design is then accomplished that is dependent on confirmation of the water table level. After the 7 day waiting period, this design is then submitted to the municipality for a permit. The permit process can take 5-10 days dependant on the work load at the city permit center. We recommend excavating test holes in the period May-November in order to catch the high water table but avoid breakup time which can cause artificially high water tables in some areas.
Once a permit is obtained the excavation work can begin. At the same time, a home builder can apply for a land use permit as this permit is dependant on having the well and septic permit in hand.
As the septic system is installed the design engineer will inspect the installation to be reasonably certain that it is being installed as designed and that soil conditions match that which where encountered during the test holes phase. The installation is documented and asbuilt records are submitted to the Municipal Onsite Services for final "asbuilt" approval. You are now well on your way to building your Alaska Dream Home!
If your lender requires, there may be one more trip by the engineer to sample the well water quality, check the well seal and final grade and submit for a final Health Approval from the Municipality also known as a "Blue Card".